Many computers today have radios to support wireless communication. Wireless communication is used, for example, to connect to an access point of a network. By associating with the access point, a wireless computer can access devices on the network or to other networks reachable through that network, such as the Internet. As a result, the wireless computer can exchange data with many other devices, enabling many useful functions.
To enable computers to be configured for association with an access point, it is common for the access points to operate according to a standard. A common standard for devices that connect to access points is called Wi-Fi. This standard was promulgated by the Wi-Fi Alliance, and is widely used in portable computers. There are multiple versions of this standard, but any of them can be used to support connections through access points.
Wireless communications may also be used to form connections directly to other devices without using an access point. These connections are sometimes called “peer-to-peer” connections and may be used, for example, to allow a computer to connect to a mouse or keyboard wirelessly. Wireless communications for these direct connections also have been standardized. A common standard for such wireless communications is called BLUETOOTH®.
In some instances, a wireless computer may concurrently connect to other devices through an access point and as part of a group engaging in peer-to-peer communications. To support such concurrent communication, some computers have multiple radios. More recently a standard has been proposed, called Wi-Fi Direct, that enables both an infrastructure connection and communication as part of a peer-to-peer group with similar wireless communications that can be processed with a single radio. This standard, also published by the Wi-Fi Alliance, extends the popular Wi-Fi communications standard for infrastructure-based communications to support direct connections.
Such direct connections may be formed among groups of devices. In accordance with the Wi-Fi Direct standard, devices that wish to communicate may exchange messages, formatted as action frames, to form a group. Initially forming a group may require user input, such as to enter a PIN or other information that serves to authorize devices to connect with one another. This process of forming an initial connection is sometimes called “pairing.”
The Wi-Fi Direct standard includes a mechanism by which devices retain information about other devices with which they have paired. In this way, devices may form persistent groups such that the devices can communicate if a connection between the devices is interrupted. Such a disruption can happen, for example, if one device is turned off or the devices move out of communication range. When the connection between devices in a persistent group is broken, if those devices are later able to support a connection between them, the peer to peer group may automatically reform without user action. In accordance with the Wi-Fi Direct standard, groups, once formed, are identified by a hardware identifier of a device controlling the group. Because the hardware identifier will be persistent for the lifetime of a device and is included in beacons sent by a device available for formation of a group, other devices can identify “known” devices for which a group has already been formed. When it is possible to reestablish a connection with those devices, a group may be re-formed using stored information, without the need to repeat the pairing process.